Hurricane Sandy's huge size: freak of nature or climate change?
Hurricane Sandy was truly astounding in its size and power. At its peak size, twenty hours before landfall, Sandy had tropical storm-force winds that covered an area nearly one-fifth the area of the contiguous United States. Since detailed records of hurricane size began in 1988, only one tropical storm (Olga of 2001) has had a larger area of tropical storm-force winds, and no hurricanes has. Sandy's area of ocean with twelve-foot seas peaked at 1.4 million square miles--nearly one-half the area of the contiguous United States, or 1% of Earth's total ocean area. Most incredibly, ten hours before landfall (9:30 am EDT October 30), the total energy of Sandy's winds of tropical storm-force and higher peaked at 329 terajoules--the highest value for any Atlantic hurricane since at least 1969. This is 2.7 times higher than Katrina's peak energy, and is equivalent to five Hiroshima-sized atomic bombs. At landfall, Sandy's tropical storm-force winds spanned 943 miles of the the U.S. coast. No hurricane on record has been wider; the previous record holder was Hurricane Igor of 2010, which was 863 miles in diameter. Sandy's huge size prompted high wind warnings to be posted from Chicago to Eastern Maine, and from Michigan's Upper Peninsula to Florida's Lake Okeechobee--an area home to 120 million people. Sandy's winds simultaneously caused damage to buildings on the shores of Lake Michigan at Indiana Dunes National Lakeshore, and toppled power lines in Nova Scotia, Canada--locations 1200 miles apart!
Largest Atlantic tropical cyclones for area covered by tropical storm-force winds:
Olga, 2001: 780,000 square miles
Sandy, 2012: 560,000 square miles
Lili, 1996: 550,000 square miles
Igor, 2010: 550,000 square miles
Karl, 2004: 430,000 square miles
Figure 1. Hurricane Sandy’s winds (top), on October 28, 2012, when Sandy was a Category 1 hurricane with top winds of 75 mph (this ocean surface wind data is from a radar scatterometer on the Indian Space Research Organization’s (ISRO) Oceansat-2.) Hurricane Katrina’s winds (bottom) on August 28, 2005, when Katrina was a Category 5 hurricane with top winds of 175 mph (data taken by a radar scatterometer on NASA’s defunct QuickSCAT satellite.) In both maps, wind speeds above 65 kilometers (40 miles) per hour are yellow; above 80 kph (50 mph) are orange; and above 95 kph (60 mph) are dark red. The most noticeable difference is the extent of the strong wind fields. For Katrina, winds over 65 kilometers per hour stretched about 500 kilometers (300 miles) from edge to edge. For Sandy, winds of that intensity spanned an region of ocean three times as great--1,500 kilometers (900 miles). Katrina was able to generate a record-height storm surge over a small area of the Mississippi coast. Sandy generated a lower but highly destructive storm surge over a much larger area, due to the storm's weaker winds but much larger size. Image credit: NASA.
How did Sandy get so big?
We understand fairly well what controls the peak strength of a hurricane's winds, but have a poor understanding of why some hurricanes get large and others stay small. A number of factors probably worked together to create a "prefect storm" situation that allowed Sandy to grow so large, and we also must acknowledge that climate change could have played a role. Here are some possible reasons why Sandy grew so large:
1) Initial size of the disturbance that became Sandy was large
Sandy formed from an African tropical wave that interacted with a large area of low pressure that covered most of the Central Caribbean. Rotunno and Emanuel (1987) found that hurricanes that form from large initial tropical disturbances like Sandy did tend to end up large in size.
Figure 2. The initial disturbance that spawned Sandy, seen here on October 20, 2012, was quite large.
2) High relative humidity in Sandy's genesis region
The amount of moisture in the atmosphere may play an important role in how large a hurricane gets (Hill and Lackmann, 2009.) Sandy was spawned in the Caribbean in a region where the relative humidity was near 70%. This is the highest humidity we saw during 2012 during the formation of any Atlantic hurricane.
3) Passage over Cuba
Sandy struck Cuba as an intensifying Category 2 hurricane with 110 mph winds. While the core of the storm was over Cuba, it was cut off from the warm ocean waters surrounding Cuba. Most of Sandy's large circulation was still over the ocean, though, and the energy the storm was able to extract from the ocean went into intensifying the spiral bands over water. When Sandy's core re-emerged over water, the hurricane now had spiral bands with heavier thunderstorm activity as a result of the extra energy pumped into the outer portion of the storm during the eye's passage over land. This extra energy in the outer portions of Sandy may have enabled it to expand in size later.
4) Interaction with a trough of low pressure over the Bahamas
As Sandy passed through the Bahamas on October 25, the storm encountered strong upper-level winds associated with a trough of low pressure to the west. These winds created high wind shear that helped weaken Sandy and destroy the eyewall. However, Sandy compensated by spreading out its tropical storm-force winds over a much wider area. Between 15 and 21 UTC on October 25, Sandy's area of tropical storm-force winds increased by more than a factor of two.
5) Leveraging of the Earth's spin
As storms move towards Earth's poles, they acquire more spin, since Earth's rotation works to put more vertical spin into the atmosphere the closer one gets to the pole. This extra spin helps storms grow larger, and we commonly see hurricanes grow in size as they move northwards.
6) Interaction with a trough of low pressure at landfall
As Sandy approached landfall in New Jersey, it encountered an extratropical low pressure system to its west. This extratropical storm began pumping cold air aloft into the hurricane, which converted Sandy into an extratropical low pressure system, or "Nor'easter". The nature of extratropical storms is to have a much larger area with strong winds than a hurricane does, since extratropical storms derive their energy from the atmosphere along a frontal boundary that is typically many hundreds of miles long. Thus, as Sandy made landfall, the hurricane's strongest winds spread out over a larger area, causing damage from Indiana to Nova Scotia.
Are we likely to see more such storms in the future?
Global warming theory (Emanuel, 2005) predicts that a 2°C (3.6°F) increase in ocean temperatures should cause an increase in the peak winds of the strongest hurricanes of about about 10%. Furthermore, warmer ocean temperatures are expected to cause hurricanes to dump 20% more rain in their cores by the year 2100, according to computer modeling studies (Knutson et al., 2010). However, there has been no published work describing how hurricane size may change with warmer oceans in a future climate. We've seen an unusual number of Atlantic hurricanes with large size in recent years, but we currently have no theoretical or computer modeling simulations that can explain why this is so, or if we might see more storms like this in the future. However, we've seen significant and unprecedented changes to our atmosphere in recent decades, due to our emissions of heat-trapping gases like carbon dioxide. The laws of physics demand that the atmosphere must respond. Atmospheric circulation patterns that control extreme weather events must change, and we should expect extreme storms to change in character, frequency, and intensity as a result--and not always in the ways our computer models may predict. We have pushed our climate system to a fundamentally new, higher-energy state where more heat and moisture is available to power stronger storms, and we should be concerned about the possibility that Hurricane Sandy's freak size and power were partially due to human-caused climate change.
References
Emanuel, K. (2005). Increasing destructiveness of tropical cyclones over the past 30 years. Nature, 436(7051), 686-688.
Hill, Kevin A., and Gary M. Lackmann (2009), "Influence of environmental humidity on tropical cyclone size," Monthly Weather Review 137.10 (2009): 3294-3315.
Knutson, T. R., McBride, J. L., Chan, J., Emanuel, K., Holland, G., Landsea, C., ... & Sugi, M. (2010). Tropical cyclones and climate change. Nature Geoscience, 3(3), 157-163.
Rotunno, R., & Emanuel, K. A. (1987). An air–sea interaction theory for tropical cyclones. Part II: Evolutionary study using a nonhydrostatic axisymmetric numerical model. J. Atmos. Sci, 44(3), 542-561.
The Atlantic is quiet, but a Nor'easter expected next week
The Atlantic is quiet, with no threat areas to discuss. An area of low pressure is predicted to develop just north of Bermuda on Wednesday, and the GFS model predicts that this low could become a subtropical cyclone as moves north-northeastwards out to sea late in the week.
The long-range models are in increasing agreement that a Nor'easter will develop near the North Carolina coast on Sunday, then move north to northeastwards early next week. High winds, heavy rain, and coastal flooding could affect the mid-Atlantic coast and New England coasts next Monday and Tuesday due to this storm, but it appears likely that the Nor'easter will stay farther out to sea than the last Nor'easter and have less of an impact on the region devastated by Sandy. Ocean temperatures off the coast of North Carolina were cooled by about 4°F (2.2°C) due to the churning action of Hurricane Sandy's winds, but are still warm enough at 22 - 24°C to potentially allow the Nor'easter to acquire some subtropical characteristics. I doubt the storm would be able to become a named subtropical storm, but it could have an unusual amount of heavy rain if it does become partially tropical. The Nor'easter is still a long ways in the future, and there is still a lot of uncertainty on where the storm might go.
Jeff Masters
Reader Comments
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I think you know that...
Medieval Period:-
"Most scholars associate the beginning of the period with the collapse of the Roman empire, which began in 410 AD. Scholars similarly disagree about when the period ends, whether they place the end at the start of the 15th century."
Posting a graph which starts at 1600AD is not really representative of the medieval period. The records from this period are at best a trifle thin on the ground. Accurate measurement of sun radiation and other natural events was somewhat limited as the learned Europeans had not yet grasped that the world was a sphere which they could sail round.
Speculation about odd brief warm and cold periods is probably pointless as they were natural events and we are making an UN-natural event.
*facepalm*
The chart you posted does not cover the Medieval Warm Period (roughly 950 - 1250 AD).
So you want to believe all that HAARP stuff? Though I have no idea where you get the numbers--you realize that's less than a Happy Meal?
As opposed to the underlying ideology of most AGW theory proponents?
This is why the AGW debate ends up being futile. The back and forth of normal discussion ends up being two sides yelling in each other's ears with megaphones.
Even though climate change is a topic of this thread, it seems some (not you) find the discussion distracting. Later. No minds will be changed here.
I love your turn of phrase. You make me grin. :)
I resent the "fly-covered" part.
Edit: Flies do have integrity.
Still visable on the MTSAT Visible Loop
OK, let me posit:
How, exactly, is it that you propose that we're essentially going to pump out all of the stored carbon from a bunch of dead organisms from way back during some of the hottest climates on earth, and we're going to put it back in the atmosphere while simultaneously doing tons of deforestation, and we're going to do that in a very small time span as far as the earth is concerned, and it's going to just be a wee little nothing in terms of effects?
You realize that we're bringing the carbon cycle back to where it was when those dead things we're burning got super buried, right? I mean, ecologically, that's what we're doing -- we're taking dead stuff from the Mesozoic, which was relatively hot, that got caught up and stored in specific ways that had them locked up on huge time scales, and we're bringing those stored elements back to the functional biosphere at a bazillion times the rate at which they were originally removed.
How does that not lead to huge change?
(The degree of change we're looking at _is_ still a debatable point, as are many of the specifics -- but given that we're seeing effects now that models suggested shouldn't be coming for another several decades or more, I think it might be wise to err on the side of "crap, that could suck." Because you can't take it back, once you find out it's worse than you thought.)
And my point- for the last time, I know you are tired of reading this, all of you- humans were able to overpopulate because of use of fossil fuels for energy. Use of fossil fuels for energy is what is driving climate change. I am not arguing the point that warming did or did not cause extinctions, although it is part of the picture. I wanted to make the point of what IS driving the extinctions... humans using fossil fuels.
Kind of like responding to a lightning caused forrest fire and throwing gasoline on it.
Still visable on the MTSAT Visible Loop
Ha! Well, mosquitoes are _technically_ a kind of fly, so I was going to argue, but I'm not sure I would doubt their integrity, either. They're just being annoying, disease-spreading little blood-sucking jackasses because, you know, everybody's gotta make a living somehow...
So... nature didn't figure on fossil fuels causing overpopulation. Bet it would take back that "let's make sex feel good" option.
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"Funny, I can find writings that contradict the claims" - Writings??Please!! You need to present solid, peer-reviewed climate science - or summaries of that science - to support your claims.
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Lurky McLukerson had a good point: "One of the things I note frequently in these discussions is that it feels like a number of folks take "ah ha! You don't have a quick yes/no or a number to give me!" as "winning" some point."
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The denialists here seem to be quite unaware of basic physics, thermodynamics, the concept of heat, heat transfer and heat storage - that air temperature measurements are not the only indicator of global "warming."
Global warming does not mean "fairly uniform increases in global atmospheric temperature." With all this talk about bits and pieces - very tiny bits and pieces of data related AGW/CC, I've come to realize that most of you don't have a clue about the body of evidence that supports the consensus by climate scientists. A consensus that not only acknowledges the existence of AGW/CC, but also the dangers it presents to the delicate balance of "nature" that supports modern human civilization.
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AGWcreationists: So then to satisfy you, I would have to prove a negative - that AGW is not happening.
No - you would have to prove that the climate is stable, or totally accounted for by natural causes.
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Nearly every major scientific organization around the world supports AGW and has those supporting views posted on their websites. The few that are neutral are tied to the fossil fuel industry. And there are ZERO scientific organizations that support contrarian views.
Link
1. 2007 In preparation for the 33rd G8 summit, the Network of African Science Academies - Cameroon, Ghana, Kenya, Madagascar, Nigeria, Senegal, South Africa, Sudan, Tanzania, Uganda, Zambia, Zimbabwe, as well as the
2. 2007 The national science academies of the G8+5 nations - The thirteen signatories were the national science academies of Brazil, Canada, China, France, Germany, Italy, India, Japan, Mexico, Russia, South Africa, the United Kingdom, and the United States.
3. African Academy of Sciences.
4. American Association for the Advancement of Science
5. American Chemical Society
6. American Geophysical Union
7. American Institute of Physics
8. American Meteorological Society
9. American Physical Society
10. American Quaternary Association
11. American Society of Agronomy
12. Australian Institute of Physics
13. Australian Meteorological and Oceanographic Society
14. Canadian Foundation for Climate and Atmospheric Sciences
15. Canadian Meteorological and Oceanographic Society
16. Crop Science Society of America
17. European Academy of Sciences and Arts
18. European Federation of Geologists
19. European Geosciences Union
20. European Physical Society
21. European Science Foundation
22. Federation of Australian Scientific and Technological Societies
23. Geological Society of America
24. Geological Society of London
25. InterAcademy Council
26. Intergovernmental Panel on Climate Change (IPCC)
27. International Council of Academies of Engineering and Technological Sciences
28. International Union for Quaternary Research
29. International Union of Geodesy and Geophysics
30. Meteorology and oceanography
31. National Association of Geoscience Teachers
32. Polish Academy of Sciences
33. Royal Meteorological Society (UK)
34. Royal Society of New Zealand
35. Soil Science Society of America
36. The intergovernmental Arctic Council - Arctic Climate Impact Assessment
37. The Royal Society of the United Kingdom
38. U.S. Global Change Research Program
39. World Meteorological Organization
Link
"(The degree of change we're looking at _is_ still a debatable point, as are many of the specifics -- but given that we're seeing effects now that models suggested shouldn't be coming for another several decades or more, I think it might be wise to err on the side of "crap, that could suck." Because you can't take it back, once you find out it's worse than you thought.)"
310. goosegirl1
"I wanted to make the point of what IS driving the extinctions... humans using fossil fuels."
------------------------------------------------- ---
The 2 Quotes above represent some of the window from which humanity is seeing the future. WE are now chopping down forests to grow crops to make pseudofossil fuels from, what next boiling down animal remains to make diesel fuel?
The final frontier must be; are machines more important than people and are people more important than the rest of Earths life forms?
temperatures dropping here with the passage of the cold front..have a nice evening..maybe we can start over tomorrow?
I don't think that was exactly an option... more like, "if it feels good, let's do it more often." Thus a group of primates evolved, loving what makes even more primates :)
That is a good point too... I like that cartoon!
Yeah, nature doesn't really mind either way. We'll afterglow ourselves into hell, ha.
No, seriously, population becomes a flat unavoidable topic when you dig into this stuff. I don't think people realize some of what it _means_ to have this many humans --
Every living thing requires resources, and there are only so many around...
For me, though I already got it on a conceptual plane, I think that looking at the actual numbers of species anywhere near where we are on the food chain -- species we consider "abundant" -- was a real eye opener, early in my education.
How many actual bears -- individual bears, of any bear species on earth? About a million or two.
That's _it_. "Abundant," outside of a few specific kinds.
~200,000 "brown bears." Abundant. That's for the planet.
How many humans? Multiply that total bear population by a thousand, and you're not there yet...
But then, if you want to talk population, you have to talk econ, because there is no way I'm going into some of the poorest countries on earth, where people are sometimes _literally_ eating dirt -- wish I were joking, but I'm not, it's a way to fill the stomach in Haiti (and hey, maybe it has some bits of something that can break down helpfully, right?) -- and telling them what to do, while I sit here trying to ponder chicken recipes for tonight.
But CO2 is the only player in the game, right!
Then SUV's must have made the Great Lakes?
Think about it.......
Gnight>
One thing I don't get: Even if the human burning of fossil fuels has absolutely nothing to do with the clear warming trend we've seen in the past 100-200 years, which is highly unlikely, almost impossible in my opinion, what exactly is wrong with trying to decrease our dependence on fossil fuels, which we will eventually use up, anyways? Certainly slowing AGW is reason enough but even if you don't believe we affect the climate, what exactly is wrong with an agenda of decreasing our use of fossil fuels and exploring alternative energy??
40. Commonwealth Scientific and Industrial Research Organisation
The fact that you would consider that trivial, given the scale of matter involved in that 1.4 degrees, and the energy calculations involved in changing something that size by _1.4 degrees_ on average, in a tiny amount of time, geologically...
That speaks volumes.
Satellite images of the eclipse.
Still visable on the MTSAT Visible Loop
In general, nothing is wrong with it. However, there are a lot of vested interests totally opposed to any such investigation until the last drop has fuelled their profits. It is not unlike finding a cure for cancer. The economic weight of the fossil-fuel industries/cancer-cure industries is so great that there is an inherent, heavily-weighted counter to actually solving the problems. (No, that doesn't mean that I think there is a conspiracy.)
Wish I could've been there, I feel like it'd be so cool to see a solar eclipse. Very nice images.
The temperature change is not uniform. The 1.4 C figure actually obscures the changes going on at the poles and elsewhere.
Oh, yeah, I know. But even just averaged, it's a staggering amount of change on the scale involved, given the timeframe. It is not easy, energetically, to heat stuff.
Just looking at the average, it screams to me "insane amount of energy added to this complex system."
And then you get into the ways it actually works, which yeah, aren't uniform, and wow, we are looking at some consequences already.
Probably at least deserves a 10%, though I don't think it will develop.
Way back in 1972, a group of us hitchhiked to Antigonish, Nova Scotia to see the total eclipse of the sun. (no Lear jets were involved...)
It was truly an amazing experience. A one of things I remember was that all the shore birds came into shore like it was evening and then went back out again a little while later when the eclipse was over . I bet they were wondering what the heck was going on.
Thanks for posting the eclipse images and info, Aussie...brings back good memories.
It kind of hurts to see a reasonably knowledgeable person post a picture of two little girls arguing as his view of the AGW/CC debate. They are about the same age of two of my granddaughters.
The subject being discussed is the very real threat to the future in which these children will live as adults - probably a very sad future if something drastic is not done very soon to attempt to halt and reverse AGW/CC.
As ocean waters have warmed, fishermen have been finding some species that their grandfathers and even their fathers never dreamed of seeing. A 2009 report by the National Oceanic and Atmospheric Administration’s Northeast Fisheries Science Center found that about half of the species it studied were shifting their range further north or into deeper water in search of colder water, including Atlantic cod, haddock, and hake species—the keystones of New England’s iconic groundfishery. The commercial lobster fishery has all but disappeared in the waters of southern New England. And on the Pacific northwest, oyster farming is threatened by ocean acidification, a phenomenon caused by higher carbon concentrations in seawater.
It was the most intense winter storm ever recorded.
You can not make Mother Nature change either. The Gal does what she wants! And she has no President!
http://newswatch.nationalgeographic.com/2012/11/0 2/fish-on-fridays-hurricane-sandy-climate-change-a nd-the-future-of-fish/
thanks for taken the time today to have a civil discussion with me today have respect for the way you handle yourself....
Attempt to reverse? Do you have any idea what it takes to stop a MASSIVE amount of energy?
It may be a small % increase, but it's still a massive amount of air you'll have to cool.
I suggest we start adapting to what ever changes may come, I wouldn't count on being able to stop AGW damage done by foreign countries.
...keep in mind I'm not encouraging a succession, nor do I think it will occur. I'm just encouraging those individual idiots to leave my country.
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